The AD650 V/F/V (voltage-to-frequency or frequency-to-voltage converter) provides a combination of high frequency operation and low nonlinearity previously unavailable in monolithic form. The inherent monotonicity of the V/F transfer function makes the AD650 useful as a high-resolution analog-to-digital converter. A flexible input configuration allows a wide variety of input voltage and current formats to be used, and an open-collector output with separate digital ground allows simple interfacing to either standard logic families or opto-couplers.
The linearity error of the AD650 is typically 20 ppm (0.002% of full scale) and 50 ppm (0.005%) maximum at 10 kHz full scale. This corresponds to approximately 14-bit linearity in an analog-to-digital converter circuit. Higher full-scale frequencies or longer count intervals can be used for higher resolution conversions. The AD650 has a useful dynamic range of six decades allowing extremely high resolution measurements. Even at 1 MHz full scale, linearity is guaranteed less than 1000 ppm (0.1%) on the AD650KN, KP, BD and SD grades.
In addition to analog-to-digital conversion, the AD650 can be used in isolated analog signal transmission applications, phased locked-loop circuits, and precision stepper motor speed controllers. In the F/V mode, the AD650 can be used in precision tachometer and FM demodulator circuits.
The input signal range and full-scale output frequency are user-programmable with two external capacitors and one resistor. Input offset voltage can be trimmed to zero with an external potentiometer.
The AD650JN and AD650KN are offered in a plastic 14-pin DIP package. The AD650JP and AD650KP are available in a 20-pin plastic leaded chip carrier (PLCC). Both plastic packaged versions of the AD650 are specified for the commercial (0°C to +70°C) temperature range. For industrial temperature range (-25°C to +85°C) applications, the AD650AD and AD650BD are offered in a ceramic package. The AD650SD is specified for the full -55°C to +125°C extended temperature range.
|Title||Content Type||File Type|
|AD650: Voltage-to-Frequency and Frequency-to-Voltage Converter Data Sheet (Rev E, 03/2013) (pdf, 434 kB)||Data Sheets|
|AN-361: Ask the Applications Engineer (V/F Converters) (pdf, 287 kB)||Application Notes|
|AN-279: Using the AD650 Voltage-to-Frequency Converter As a Frequency-to-Voltage Converter (pdf, 80 kB)||Application Notes|
|AN-276: Analog to Digital Conversion by Using V/F Converters (pdf, 646 kB)||Application Notes|
DDS IC Plus Frequency-To-Voltage Converter Make Low-Cost DAC
by Noel McNamara, Analog Devices, Inc. (EDN Design Idea, 2/5/2004)
Ask The Applications Engineer-3
(Analog Dialogue, 30th Anniversary Reader Bonus)
|RAQs index||Rarely Asked Questions||HTML|
|What is a Voltage to Frequency Converter (VFC) and how can the be used to send analog signals over long distances without loss of accuracy?||FAQs/RAQs||HTML|
|Glossary of EE Terms||Glossary||HTML|
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AD650 Component Selection Calculator
This tool calculates values for Cint, Rint, and Cos for frequency-to-voltage and voltage-to-frequency applications of the AD650. Calculated values may be adjusted to see the effect on the outputs.
Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.